État nucléaire des méristèmes du pois dans la graine sèche; imbibition et reprise du cycle cellulaire

1985 ◽  
Vol 63 (12) ◽  
pp. 2200-2208 ◽  
Author(s):  
E. Schatt ◽  
P. Landré ◽  
A. Nougarède
Keyword(s):  
Cell Cycle ◽  
Shoot Apex ◽  
Root Apex ◽  
Organ Specificity ◽  
Light Conditions ◽  
Fresh Weight ◽  
Meristematic Cells ◽  
Root Meristematic Cells ◽  
Dark Conditions ◽  
S Period

In the dry seed of pea (Pisum sativum cv. Nain Hâtif d'Annonay), the shoot and root meristematic cells are arrested at specific phases of the cell cycle, showing organ specificity. The root apex contains resting nuclei both at the 2C- and 4C-DNA levels in approximately the same proportions; the shoot apex possesses nuclei arrested only at the 2C-DNA level. The emergence of the radicle (20th–24th hour) follows a 100% increase in fresh weight (16th hour) and is due to cell elongation only. Under dark conditions, this emergence occurs at the same time than the beginning of the S period (24th hour) from the 2C nuclei of root meristematic cells. The first mitoses of 4C nuclei occur only at the 26th hour of imbibition. In the shoot apex, the cell cycle does not start with the 2C nuclei entering the S period before the 36th hour under dark conditions, and later, in light conditions. The first mitoses begin around the 48th hour, suggesting a S + G2 period of about 12 h. These data are discussed in relation to the mechanisms responsible for the various types of blockage or control of the cell cycle.

Changes of dictyosome ultrastructure during the cell cycle in onion root meristematic cells. A morphometric and stereological study

PROTOPLASMA ◽  
1988 ◽  
Vol 146 (1) ◽  
pp. 35-40 ◽  
Author(s):  
J. A. Gonzalez-Reyes ◽  
F. Grac�a-Navarro ◽  
G. Garcia-Herdugo ◽  
P. Navas
Keyword(s):  
Cell Cycle ◽  
Onion Root ◽  
Meristematic Cells ◽  
Root Meristematic Cells

scholarly journals Accumulation of Phenolic Compounds and Glucosinolates in Sprouts of Pale Green and Purple Kohlrabi (Brassica oleracea var. gongylodes) under Light and Dark Conditions

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1939
Author(s):  
Ramaraj Sathasivam ◽  
Min Cheol Kim ◽  
Hyeon Ji Yeo ◽  
Bao Van Nguyen ◽  
Soo In Sohn ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Brassica Oleracea ◽  
Root Length ◽  
Dry Weight ◽  
Light Treatment ◽  
Total Phenolic ◽  
Light Conditions ◽  
Fresh Weight ◽  
Dark Conditions ◽  
Pale Green

Kohlrabi is considered an important dietary vegetable worldwide. In this study, we investigated the growth and accumulation of phenolic compounds (PCs) and glucosinolates in sprouts of pale green and purple kohlrabi (Brassica oleracea var. gongylodes) in response to light and dark conditions. Pale green kohlrabi presented high fresh weight and root length irrespective of light treatment, whereas under dark conditions, it presented higher fresh weight and shoot length than purple kohlrabi. In contrast, the root length of both kohlrabies increased markedly under light conditions compared to that under dark conditions. Thirteen PCs and eight glucosinolates were detected and quantified in 10-day-old pale green and purple kohlrabies. In both kohlrabies, the individual and total phenolic levels were much higher under the light treatment than under the dark treatment. Under light and dark conditions, the total phenolic content was 6362.13 and 5475.04 µg/g dry weight in the pale green kohlrabi, respectively, whereas in the purple kohlrabi, it was 10,115.76 and 9361.74 µg/g dry weight, respectively. Dark conditions favored higher accumulation of glucosinolates than light conditions. Progoitrin, neoglucobrassicin, glucoerucin, and 4-methoxyglucobrassicin were the predominant glucosinolates in both kohlrabies and were present in much higher amounts in the pale green kohlrabi. In pale green kohlrabi under dark conditions, the total glucosinolates content was 4.75 and 2.62 times higher than that of the purple kohlrabi under light and dark conditions, respectively. Among individual glucosinolates, in the pale green kohlrabi under the dark condition, progoitrin was found to have the highest content, which was 90.28 and 54.51 times higher than that in the purple kohlrabi under light and dark conditions, respectively. These results show that the phenolic and glucosinolates levels varied widely, and these variations between the two types of kohlrabi under both light and dark conditions were significant. Our findings suggest that light and dark conditions enhance the accumulation of PCs and glucosinolates, respectively, during the development of kohlrabi seedlings.

Des variations d'activités de la 5′-nucléotidase et de l’adénylate-cyclase sont-elles des composantes de la levée d'inhibition du bourgeon cotylédonaire du pois?

1985 ◽  
Vol 63 (2) ◽  
pp. 309-323 ◽  
Author(s):  
Arlette Nougarède ◽  
Pierre Landré ◽  
Jacques Rembur ◽  
Mercedes Niebla Hernandez
Keyword(s):  
Cell Cycle ◽  
Alkaline Phosphatase ◽  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Sodium Fluoride ◽  
Shoot Apex ◽  
Cotyledonary Node ◽  
Ultrastructural Level ◽  
Meristematic Cells ◽  
Plant Enzyme

Adenylate cyclase and 5′-nucleotidase activities were localized at the ultrastructural level. Variations of these activities were checked in the transfer cells of the cotyledonary node in the intact or decapitated plant. They were also studied in the shoot apex of both inhibited (G0 state) and released cotyledonary buds, during the transitions G1–S orG2–M. The adenylate cyclase activity is mainly associated with the exterior side of the plasma membrane and it is identical in both specialized and meristematic cells, no matter what the phase of the cell cycle is. Sodium fluoride did not appear as an activator of the plant enzyme adenylate cyclase. The 5′-nuelcotidase activity was predominant on the outside of the plasma membrane and in the plasmodesmata with no variation of intensity in the meristematic cells of the bud in relation to the cell cycle phases. Use of inhibitors of alkaline phosphatase (L-p-bromotetramisole and L-phenylalanine) and 5′-nucleotidase activities (α-β-methylene adenosine 5′-diphosphate) demonstrated the specificity of the reaction along the plasma membrane. The constancy of adenylate cyclase and 5′-nucleotidase activities in both inhibited and released buds suggests that if the optimization of the pool of polynucleotides is a component of the release from inhibition in the cotyledonary bud of pea, it is not due to the variation of activities of enzymes which release adenosine from ATP.

The relationship between the mitotic activity and moisture content of recalcitrant seeds ofAcer saccharinum(L.) during maturation, post-maturation drying and germination

2000 ◽  
Vol 10 (3) ◽  
pp. 225-232 ◽  
Author(s):  
L.E. Kozeko ◽  
V.M. Troyan
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Moisture Content ◽  
Mitotic Activity ◽  
Shoot Apex ◽  
Root Apex ◽  
Recalcitrant Seeds ◽  
Orthodox Seeds ◽  
The Relationship ◽  
Mature Seeds

AbstractThe decline of embryo moisture content from approx. 82 to 53% in 1997 and 56% in 1998 in recalcitrant seeds ofAcer saccharinumduring maturation was accompanied by decreased mitotic activity in the meristems and an increase in the percentage of cells in the G1phase of the cell cycle. DNA synthesis and mitosis in the root apex ceased at approx. 53% embryo moisture content, and 67% of the cells were arrested in the G1phase. During post-maturation drying, cell division in the shoot apex and embryonic leaves continued as long as the embryo moisture content was higher than 50 and 45%, respectively. Mitotic activity in the drying embryo may be controlled by its moisture level. Increased proliferation of the root, shoot and leaf meristems of the mature seeds was already recorded at 24 h of germination, before the root protruded through the seed coat. However, the increase in the embryo moisture content was small – from 56 to 59%. In the 3 d seedlings (10–15 mm long) the mitotic index reached 8% in the root apex and 12% in the shoot apex with leaves. Placing mature seeds in moist conditions might be necessary for the switch from proliferation decline towards its activation. Thus, in contrast with orthodox seeds, the preservation of cell division capacity and increased mitotic activity may be essential for rapid germination immediately after shedding in matureAcerseeds.

scholarly journals Sensitivity of the Cell Division Cycle to α-Amanitin In ALLIUM ROOT TIPS

1974 ◽  
Vol 14 (3) ◽  
pp. 461-473
Author(s):  
C. DE LATORRE ◽  
M. E. FERNANDEZ-GOMEZ ◽  
G. GIMENEZ-MARTIN ◽  
A. GONZALEZ-FERNANDEZ
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Normal Structure ◽  
Cell Division Cycle ◽  
The Other ◽  
Root Tips ◽  
Meristematic Cells ◽  
Normal Duration ◽  
S Period ◽  
Nucleolar Rna

The effect of α-amanitin on the cell cycle in Allium cepa meristematic cells was studied: the G1 and G2 periods are prolonged respectively to 1.9 and 1.7 times the normal duration; the S-period is lengthened very little; and the prophase of mitosis is increased to twice the normal duration. It is postulated that real differences in the activity of the non-nucleolar RNA poly-merase might exist in the course of the cell division cycle and that they would account for the higher sensitivities shown by G1, G2 and prophase. On the other hand, the interphase nucleolus responds by segregation in the first few hours of α-amanitin treatment, but recovers its normal structure in continued presence of the drug; and nucleolar reorganization is inhibited in the first few hours in recently formed cells, but the process is subsequently speeded up to attain the same value 4 h after the treatment was begun as in untreated cells.

Tissue specificity of expression of heat shock gene ATHSP70-10 in Arabidopsis thaliana seedlings under normal and stress conditions

2020 ◽  
Vol 2020 (3) ◽  
pp. 37-47
Author(s):  
L.Ye. Kozeko ◽  
◽  
E.L. Kordyum ◽  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Shock ◽  
Water Deficit ◽  
Tissue Specificity ◽  
Abiotic Factors ◽  
Root Apex ◽  
Stress Conditions ◽  
Heat Shock Gene ◽  
Organ Specificity ◽  
Pcr Analysis

Mitochondrial heat shock proteins of HSP70 family support protein homeostasis in mitochondria under normal and stress conditions. They provide folding and complex assembly of proteins encoded by mitochondrial genome, as well as import of cytosolic proteins to mitochondria, their folding and protection against aggregation. There are reports about organ-specificity of mitochondrial HSP70 synthesis in plants. However, tissue specificity of their functioning remains incompletely characterized. This problem was studied for mitochondrial AtHSP70-10 in Arabidopsis thaliana seedlings using a transgenic line with uidA signal gene under normal conditions, as well as high temperature and water deficit. Under normal conditions, histochemical GUS-staining revealed the expression of AtHSP70-10 in cotyledon and leaf hydathodes, stipules, central cylinder in root differentiation and mature zones, as well as weak staining in root apex and root-shoot junction zone. RT-PCR analysis of wild-type seedlings exposed to 37°C showed rapid upregulation of AtHSP70-10, which reached the highest level within 2 h. In addition, the gradual development of water deficit for 5 days caused an increase in transcription of this gene, which became more pronounced after 3 days and reached a maximum after 5 days of dehydration. Histochemical analysis showed complete preservation of tissue localization of AtHSP70-10 expression under both abiotic factors. The data obtained indicate the specific functioning of mitochondrial chaperone AtHSP70-10 in certain plant cellular structures.

An Ultrastructural and Radio-Autographic Study of the Evolution of the Interphase Nucleus in Plant Meristematic Cells (Allium Porrum)

1974 ◽  
Vol 14 (2) ◽  
pp. 263-287
Author(s):  
J. G. LAFONTAINE ◽  
A. LORD
Keyword(s):  
Interphase Nucleus ◽  
Structural Changes ◽  
Tritiated Thymidine ◽  
Light And Electron Microscopy ◽  
Allium Porrum ◽  
Meristematic Cells ◽  
Fibrillar Material ◽  
Nuclear Structures ◽  
S Period ◽  
Dense Chromatin

Radioautography under both light and electron microscopy was exploited to investigate the structural changes of the chromatin reticulum which characterizes the interphase nucleus of a number of plants. Allium porrum meristematic plant cells were used for this purpose. In this species, the telophase chromosomes uncoil into dense strands which, during the G1 period, gradually give rise to a coarse reticulum. There then follows an extensive unravelling of portions of these strands, and high-resolution radioautography reveals that labelling with tritiated thymidine predominantly occurs over zones of the nucleus consisting of diffuse fine fibrillar material. As the S-period progresses, a chromatin reticulum reappears throughout the nuclear cavity, the tortuous strands being approximately 0.25 µm in diameter. Most of the radioautographic grains still remain over the light nucleoplasmic areas but a number of these are now located on the outermost portion of the dense chromatin profiles. By the end of the S-period, the chromatin strands are slightly thicker (ca. 0.3 µm) and form a looser reticulum. Labelling has decreased noticeably in nuclei of that period, the radioautographic grains being grouped into clusters resting over more or less spherical regions of the chromatin reticulum. Judging from their localization at the surface of the nucleolus or close to the nuclear envelope, these structures correspond to chromocentres. The additional interesting finding that such nuclear structures appear much less compactly organized strongly suggests that chromocentres undergo important conformational modifications during duplication of their DNA.

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